1. Field of the Invention
The present invention relates to a mechanical device used to grind down tree stumps.
2. Description of the Related Art
In land clearing operations, there is frequently a need to remove stumps after trees have been cut. Many methods and devices have been proposed for removing stumps from the earth's surface in order to allow soil tillage, building construction, etc. The related art is represented by the following patents of interest.
U.S. Pat. No. 3,044,509, issued on Jul. 17, 1962 to Jacob Keller, describes a horizontally rotating stump cutting cylinder universally mounted upon the rear end of a tractor. Keller does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 3,732,905, issued on May 15, 1973 to James M. Pickel, describes a tree stump removing apparatus for mounting on a prime mover and operative to move a vertical cutting blade laterally during the cutting action thereof. Pickel does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 4,530,385, issued on Jul. 23, 1985 to Norman N. York, describes a tree stump removal apparatus which is supported by the standard three point hitch of a tractor and is driven by the power take-off and hydraulic supply systems of the tractor. York '385 does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 4,621,668, issued on Nov. 11, 1998 to Norman N. York, describes a tree stump removal apparatus which is supported by the standard three point hitch of a tractor and is driven by the power take-off and hydraulic supply systems of the tractor. York '668 does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 4,681,145, issued on Jul. 21, 1987 to Norman N. York, describes a tree stump removal apparatus which is supported by the standard three point hitch of a tractor and is driven by the tractor power take-off, but incorporates a hydraulic supply system which is independent of the tractor hydraulic system. York '145 does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 5,435,359, issued on Jul. 25, 1995 to Robert J. Craft, describes a stump grinder having a cutting wheel with peripherally mounted cutter teeth. Craft '359 does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 5,655,581, issued on Aug. 12, 1997 to Robert J. Craft, describes a stump grinder attachment capable of being mounted on a three-point hitch of a tractor. Craft '581 does not suggest a stump grinder according to the claimed invention.
U.S. Pat. No. 5,829,497, issued on Nov. 3, 1998 to Freeman D. Muroney, describes a stump grinder designed for attachment to the three point hitch of an agricultural tractor with a stump grinding wheel driven by the tractor power takeoff. Muroney does not suggest a stump grinder according to the claimed invention.
Soviet Union Pat. document 1,240,388, published on Jun. 30, 1986, shows a tree-stump cutting machine. Soviet Union '388 does not suggest a stump grinder according to the claimed invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.